source: trip-planner-front/node_modules/pako/lib/zlib/trees.js@ eed0bf8

Last change on this file since eed0bf8 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1'use strict';
2
3// (C) 1995-2013 Jean-loup Gailly and Mark Adler
4// (C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
5//
6// This software is provided 'as-is', without any express or implied
7// warranty. In no event will the authors be held liable for any damages
8// arising from the use of this software.
9//
10// Permission is granted to anyone to use this software for any purpose,
11// including commercial applications, and to alter it and redistribute it
12// freely, subject to the following restrictions:
13//
14// 1. The origin of this software must not be misrepresented; you must not
15// claim that you wrote the original software. If you use this software
16// in a product, an acknowledgment in the product documentation would be
17// appreciated but is not required.
18// 2. Altered source versions must be plainly marked as such, and must not be
19// misrepresented as being the original software.
20// 3. This notice may not be removed or altered from any source distribution.
21
22/* eslint-disable space-unary-ops */
23
24var utils = require('../utils/common');
25
26/* Public constants ==========================================================*/
27/* ===========================================================================*/
28
29
30//var Z_FILTERED = 1;
31//var Z_HUFFMAN_ONLY = 2;
32//var Z_RLE = 3;
33var Z_FIXED = 4;
34//var Z_DEFAULT_STRATEGY = 0;
35
36/* Possible values of the data_type field (though see inflate()) */
37var Z_BINARY = 0;
38var Z_TEXT = 1;
39//var Z_ASCII = 1; // = Z_TEXT
40var Z_UNKNOWN = 2;
41
42/*============================================================================*/
43
44
45function zero(buf) { var len = buf.length; while (--len >= 0) { buf[len] = 0; } }
46
47// From zutil.h
48
49var STORED_BLOCK = 0;
50var STATIC_TREES = 1;
51var DYN_TREES = 2;
52/* The three kinds of block type */
53
54var MIN_MATCH = 3;
55var MAX_MATCH = 258;
56/* The minimum and maximum match lengths */
57
58// From deflate.h
59/* ===========================================================================
60 * Internal compression state.
61 */
62
63var LENGTH_CODES = 29;
64/* number of length codes, not counting the special END_BLOCK code */
65
66var LITERALS = 256;
67/* number of literal bytes 0..255 */
68
69var L_CODES = LITERALS + 1 + LENGTH_CODES;
70/* number of Literal or Length codes, including the END_BLOCK code */
71
72var D_CODES = 30;
73/* number of distance codes */
74
75var BL_CODES = 19;
76/* number of codes used to transfer the bit lengths */
77
78var HEAP_SIZE = 2 * L_CODES + 1;
79/* maximum heap size */
80
81var MAX_BITS = 15;
82/* All codes must not exceed MAX_BITS bits */
83
84var Buf_size = 16;
85/* size of bit buffer in bi_buf */
86
87
88/* ===========================================================================
89 * Constants
90 */
91
92var MAX_BL_BITS = 7;
93/* Bit length codes must not exceed MAX_BL_BITS bits */
94
95var END_BLOCK = 256;
96/* end of block literal code */
97
98var REP_3_6 = 16;
99/* repeat previous bit length 3-6 times (2 bits of repeat count) */
100
101var REPZ_3_10 = 17;
102/* repeat a zero length 3-10 times (3 bits of repeat count) */
103
104var REPZ_11_138 = 18;
105/* repeat a zero length 11-138 times (7 bits of repeat count) */
106
107/* eslint-disable comma-spacing,array-bracket-spacing */
108var extra_lbits = /* extra bits for each length code */
109 [0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0];
110
111var extra_dbits = /* extra bits for each distance code */
112 [0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13];
113
114var extra_blbits = /* extra bits for each bit length code */
115 [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7];
116
117var bl_order =
118 [16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15];
119/* eslint-enable comma-spacing,array-bracket-spacing */
120
121/* The lengths of the bit length codes are sent in order of decreasing
122 * probability, to avoid transmitting the lengths for unused bit length codes.
123 */
124
125/* ===========================================================================
126 * Local data. These are initialized only once.
127 */
128
129// We pre-fill arrays with 0 to avoid uninitialized gaps
130
131var DIST_CODE_LEN = 512; /* see definition of array dist_code below */
132
133// !!!! Use flat array instead of structure, Freq = i*2, Len = i*2+1
134var static_ltree = new Array((L_CODES + 2) * 2);
135zero(static_ltree);
136/* The static literal tree. Since the bit lengths are imposed, there is no
137 * need for the L_CODES extra codes used during heap construction. However
138 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
139 * below).
140 */
141
142var static_dtree = new Array(D_CODES * 2);
143zero(static_dtree);
144/* The static distance tree. (Actually a trivial tree since all codes use
145 * 5 bits.)
146 */
147
148var _dist_code = new Array(DIST_CODE_LEN);
149zero(_dist_code);
150/* Distance codes. The first 256 values correspond to the distances
151 * 3 .. 258, the last 256 values correspond to the top 8 bits of
152 * the 15 bit distances.
153 */
154
155var _length_code = new Array(MAX_MATCH - MIN_MATCH + 1);
156zero(_length_code);
157/* length code for each normalized match length (0 == MIN_MATCH) */
158
159var base_length = new Array(LENGTH_CODES);
160zero(base_length);
161/* First normalized length for each code (0 = MIN_MATCH) */
162
163var base_dist = new Array(D_CODES);
164zero(base_dist);
165/* First normalized distance for each code (0 = distance of 1) */
166
167
168function StaticTreeDesc(static_tree, extra_bits, extra_base, elems, max_length) {
169
170 this.static_tree = static_tree; /* static tree or NULL */
171 this.extra_bits = extra_bits; /* extra bits for each code or NULL */
172 this.extra_base = extra_base; /* base index for extra_bits */
173 this.elems = elems; /* max number of elements in the tree */
174 this.max_length = max_length; /* max bit length for the codes */
175
176 // show if `static_tree` has data or dummy - needed for monomorphic objects
177 this.has_stree = static_tree && static_tree.length;
178}
179
180
181var static_l_desc;
182var static_d_desc;
183var static_bl_desc;
184
185
186function TreeDesc(dyn_tree, stat_desc) {
187 this.dyn_tree = dyn_tree; /* the dynamic tree */
188 this.max_code = 0; /* largest code with non zero frequency */
189 this.stat_desc = stat_desc; /* the corresponding static tree */
190}
191
192
193
194function d_code(dist) {
195 return dist < 256 ? _dist_code[dist] : _dist_code[256 + (dist >>> 7)];
196}
197
198
199/* ===========================================================================
200 * Output a short LSB first on the stream.
201 * IN assertion: there is enough room in pendingBuf.
202 */
203function put_short(s, w) {
204// put_byte(s, (uch)((w) & 0xff));
205// put_byte(s, (uch)((ush)(w) >> 8));
206 s.pending_buf[s.pending++] = (w) & 0xff;
207 s.pending_buf[s.pending++] = (w >>> 8) & 0xff;
208}
209
210
211/* ===========================================================================
212 * Send a value on a given number of bits.
213 * IN assertion: length <= 16 and value fits in length bits.
214 */
215function send_bits(s, value, length) {
216 if (s.bi_valid > (Buf_size - length)) {
217 s.bi_buf |= (value << s.bi_valid) & 0xffff;
218 put_short(s, s.bi_buf);
219 s.bi_buf = value >> (Buf_size - s.bi_valid);
220 s.bi_valid += length - Buf_size;
221 } else {
222 s.bi_buf |= (value << s.bi_valid) & 0xffff;
223 s.bi_valid += length;
224 }
225}
226
227
228function send_code(s, c, tree) {
229 send_bits(s, tree[c * 2]/*.Code*/, tree[c * 2 + 1]/*.Len*/);
230}
231
232
233/* ===========================================================================
234 * Reverse the first len bits of a code, using straightforward code (a faster
235 * method would use a table)
236 * IN assertion: 1 <= len <= 15
237 */
238function bi_reverse(code, len) {
239 var res = 0;
240 do {
241 res |= code & 1;
242 code >>>= 1;
243 res <<= 1;
244 } while (--len > 0);
245 return res >>> 1;
246}
247
248
249/* ===========================================================================
250 * Flush the bit buffer, keeping at most 7 bits in it.
251 */
252function bi_flush(s) {
253 if (s.bi_valid === 16) {
254 put_short(s, s.bi_buf);
255 s.bi_buf = 0;
256 s.bi_valid = 0;
257
258 } else if (s.bi_valid >= 8) {
259 s.pending_buf[s.pending++] = s.bi_buf & 0xff;
260 s.bi_buf >>= 8;
261 s.bi_valid -= 8;
262 }
263}
264
265
266/* ===========================================================================
267 * Compute the optimal bit lengths for a tree and update the total bit length
268 * for the current block.
269 * IN assertion: the fields freq and dad are set, heap[heap_max] and
270 * above are the tree nodes sorted by increasing frequency.
271 * OUT assertions: the field len is set to the optimal bit length, the
272 * array bl_count contains the frequencies for each bit length.
273 * The length opt_len is updated; static_len is also updated if stree is
274 * not null.
275 */
276function gen_bitlen(s, desc)
277// deflate_state *s;
278// tree_desc *desc; /* the tree descriptor */
279{
280 var tree = desc.dyn_tree;
281 var max_code = desc.max_code;
282 var stree = desc.stat_desc.static_tree;
283 var has_stree = desc.stat_desc.has_stree;
284 var extra = desc.stat_desc.extra_bits;
285 var base = desc.stat_desc.extra_base;
286 var max_length = desc.stat_desc.max_length;
287 var h; /* heap index */
288 var n, m; /* iterate over the tree elements */
289 var bits; /* bit length */
290 var xbits; /* extra bits */
291 var f; /* frequency */
292 var overflow = 0; /* number of elements with bit length too large */
293
294 for (bits = 0; bits <= MAX_BITS; bits++) {
295 s.bl_count[bits] = 0;
296 }
297
298 /* In a first pass, compute the optimal bit lengths (which may
299 * overflow in the case of the bit length tree).
300 */
301 tree[s.heap[s.heap_max] * 2 + 1]/*.Len*/ = 0; /* root of the heap */
302
303 for (h = s.heap_max + 1; h < HEAP_SIZE; h++) {
304 n = s.heap[h];
305 bits = tree[tree[n * 2 + 1]/*.Dad*/ * 2 + 1]/*.Len*/ + 1;
306 if (bits > max_length) {
307 bits = max_length;
308 overflow++;
309 }
310 tree[n * 2 + 1]/*.Len*/ = bits;
311 /* We overwrite tree[n].Dad which is no longer needed */
312
313 if (n > max_code) { continue; } /* not a leaf node */
314
315 s.bl_count[bits]++;
316 xbits = 0;
317 if (n >= base) {
318 xbits = extra[n - base];
319 }
320 f = tree[n * 2]/*.Freq*/;
321 s.opt_len += f * (bits + xbits);
322 if (has_stree) {
323 s.static_len += f * (stree[n * 2 + 1]/*.Len*/ + xbits);
324 }
325 }
326 if (overflow === 0) { return; }
327
328 // Trace((stderr,"\nbit length overflow\n"));
329 /* This happens for example on obj2 and pic of the Calgary corpus */
330
331 /* Find the first bit length which could increase: */
332 do {
333 bits = max_length - 1;
334 while (s.bl_count[bits] === 0) { bits--; }
335 s.bl_count[bits]--; /* move one leaf down the tree */
336 s.bl_count[bits + 1] += 2; /* move one overflow item as its brother */
337 s.bl_count[max_length]--;
338 /* The brother of the overflow item also moves one step up,
339 * but this does not affect bl_count[max_length]
340 */
341 overflow -= 2;
342 } while (overflow > 0);
343
344 /* Now recompute all bit lengths, scanning in increasing frequency.
345 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
346 * lengths instead of fixing only the wrong ones. This idea is taken
347 * from 'ar' written by Haruhiko Okumura.)
348 */
349 for (bits = max_length; bits !== 0; bits--) {
350 n = s.bl_count[bits];
351 while (n !== 0) {
352 m = s.heap[--h];
353 if (m > max_code) { continue; }
354 if (tree[m * 2 + 1]/*.Len*/ !== bits) {
355 // Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
356 s.opt_len += (bits - tree[m * 2 + 1]/*.Len*/) * tree[m * 2]/*.Freq*/;
357 tree[m * 2 + 1]/*.Len*/ = bits;
358 }
359 n--;
360 }
361 }
362}
363
364
365/* ===========================================================================
366 * Generate the codes for a given tree and bit counts (which need not be
367 * optimal).
368 * IN assertion: the array bl_count contains the bit length statistics for
369 * the given tree and the field len is set for all tree elements.
370 * OUT assertion: the field code is set for all tree elements of non
371 * zero code length.
372 */
373function gen_codes(tree, max_code, bl_count)
374// ct_data *tree; /* the tree to decorate */
375// int max_code; /* largest code with non zero frequency */
376// ushf *bl_count; /* number of codes at each bit length */
377{
378 var next_code = new Array(MAX_BITS + 1); /* next code value for each bit length */
379 var code = 0; /* running code value */
380 var bits; /* bit index */
381 var n; /* code index */
382
383 /* The distribution counts are first used to generate the code values
384 * without bit reversal.
385 */
386 for (bits = 1; bits <= MAX_BITS; bits++) {
387 next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
388 }
389 /* Check that the bit counts in bl_count are consistent. The last code
390 * must be all ones.
391 */
392 //Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
393 // "inconsistent bit counts");
394 //Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
395
396 for (n = 0; n <= max_code; n++) {
397 var len = tree[n * 2 + 1]/*.Len*/;
398 if (len === 0) { continue; }
399 /* Now reverse the bits */
400 tree[n * 2]/*.Code*/ = bi_reverse(next_code[len]++, len);
401
402 //Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
403 // n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
404 }
405}
406
407
408/* ===========================================================================
409 * Initialize the various 'constant' tables.
410 */
411function tr_static_init() {
412 var n; /* iterates over tree elements */
413 var bits; /* bit counter */
414 var length; /* length value */
415 var code; /* code value */
416 var dist; /* distance index */
417 var bl_count = new Array(MAX_BITS + 1);
418 /* number of codes at each bit length for an optimal tree */
419
420 // do check in _tr_init()
421 //if (static_init_done) return;
422
423 /* For some embedded targets, global variables are not initialized: */
424/*#ifdef NO_INIT_GLOBAL_POINTERS
425 static_l_desc.static_tree = static_ltree;
426 static_l_desc.extra_bits = extra_lbits;
427 static_d_desc.static_tree = static_dtree;
428 static_d_desc.extra_bits = extra_dbits;
429 static_bl_desc.extra_bits = extra_blbits;
430#endif*/
431
432 /* Initialize the mapping length (0..255) -> length code (0..28) */
433 length = 0;
434 for (code = 0; code < LENGTH_CODES - 1; code++) {
435 base_length[code] = length;
436 for (n = 0; n < (1 << extra_lbits[code]); n++) {
437 _length_code[length++] = code;
438 }
439 }
440 //Assert (length == 256, "tr_static_init: length != 256");
441 /* Note that the length 255 (match length 258) can be represented
442 * in two different ways: code 284 + 5 bits or code 285, so we
443 * overwrite length_code[255] to use the best encoding:
444 */
445 _length_code[length - 1] = code;
446
447 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
448 dist = 0;
449 for (code = 0; code < 16; code++) {
450 base_dist[code] = dist;
451 for (n = 0; n < (1 << extra_dbits[code]); n++) {
452 _dist_code[dist++] = code;
453 }
454 }
455 //Assert (dist == 256, "tr_static_init: dist != 256");
456 dist >>= 7; /* from now on, all distances are divided by 128 */
457 for (; code < D_CODES; code++) {
458 base_dist[code] = dist << 7;
459 for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
460 _dist_code[256 + dist++] = code;
461 }
462 }
463 //Assert (dist == 256, "tr_static_init: 256+dist != 512");
464
465 /* Construct the codes of the static literal tree */
466 for (bits = 0; bits <= MAX_BITS; bits++) {
467 bl_count[bits] = 0;
468 }
469
470 n = 0;
471 while (n <= 143) {
472 static_ltree[n * 2 + 1]/*.Len*/ = 8;
473 n++;
474 bl_count[8]++;
475 }
476 while (n <= 255) {
477 static_ltree[n * 2 + 1]/*.Len*/ = 9;
478 n++;
479 bl_count[9]++;
480 }
481 while (n <= 279) {
482 static_ltree[n * 2 + 1]/*.Len*/ = 7;
483 n++;
484 bl_count[7]++;
485 }
486 while (n <= 287) {
487 static_ltree[n * 2 + 1]/*.Len*/ = 8;
488 n++;
489 bl_count[8]++;
490 }
491 /* Codes 286 and 287 do not exist, but we must include them in the
492 * tree construction to get a canonical Huffman tree (longest code
493 * all ones)
494 */
495 gen_codes(static_ltree, L_CODES + 1, bl_count);
496
497 /* The static distance tree is trivial: */
498 for (n = 0; n < D_CODES; n++) {
499 static_dtree[n * 2 + 1]/*.Len*/ = 5;
500 static_dtree[n * 2]/*.Code*/ = bi_reverse(n, 5);
501 }
502
503 // Now data ready and we can init static trees
504 static_l_desc = new StaticTreeDesc(static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_BITS);
505 static_d_desc = new StaticTreeDesc(static_dtree, extra_dbits, 0, D_CODES, MAX_BITS);
506 static_bl_desc = new StaticTreeDesc(new Array(0), extra_blbits, 0, BL_CODES, MAX_BL_BITS);
507
508 //static_init_done = true;
509}
510
511
512/* ===========================================================================
513 * Initialize a new block.
514 */
515function init_block(s) {
516 var n; /* iterates over tree elements */
517
518 /* Initialize the trees. */
519 for (n = 0; n < L_CODES; n++) { s.dyn_ltree[n * 2]/*.Freq*/ = 0; }
520 for (n = 0; n < D_CODES; n++) { s.dyn_dtree[n * 2]/*.Freq*/ = 0; }
521 for (n = 0; n < BL_CODES; n++) { s.bl_tree[n * 2]/*.Freq*/ = 0; }
522
523 s.dyn_ltree[END_BLOCK * 2]/*.Freq*/ = 1;
524 s.opt_len = s.static_len = 0;
525 s.last_lit = s.matches = 0;
526}
527
528
529/* ===========================================================================
530 * Flush the bit buffer and align the output on a byte boundary
531 */
532function bi_windup(s)
533{
534 if (s.bi_valid > 8) {
535 put_short(s, s.bi_buf);
536 } else if (s.bi_valid > 0) {
537 //put_byte(s, (Byte)s->bi_buf);
538 s.pending_buf[s.pending++] = s.bi_buf;
539 }
540 s.bi_buf = 0;
541 s.bi_valid = 0;
542}
543
544/* ===========================================================================
545 * Copy a stored block, storing first the length and its
546 * one's complement if requested.
547 */
548function copy_block(s, buf, len, header)
549//DeflateState *s;
550//charf *buf; /* the input data */
551//unsigned len; /* its length */
552//int header; /* true if block header must be written */
553{
554 bi_windup(s); /* align on byte boundary */
555
556 if (header) {
557 put_short(s, len);
558 put_short(s, ~len);
559 }
560// while (len--) {
561// put_byte(s, *buf++);
562// }
563 utils.arraySet(s.pending_buf, s.window, buf, len, s.pending);
564 s.pending += len;
565}
566
567/* ===========================================================================
568 * Compares to subtrees, using the tree depth as tie breaker when
569 * the subtrees have equal frequency. This minimizes the worst case length.
570 */
571function smaller(tree, n, m, depth) {
572 var _n2 = n * 2;
573 var _m2 = m * 2;
574 return (tree[_n2]/*.Freq*/ < tree[_m2]/*.Freq*/ ||
575 (tree[_n2]/*.Freq*/ === tree[_m2]/*.Freq*/ && depth[n] <= depth[m]));
576}
577
578/* ===========================================================================
579 * Restore the heap property by moving down the tree starting at node k,
580 * exchanging a node with the smallest of its two sons if necessary, stopping
581 * when the heap property is re-established (each father smaller than its
582 * two sons).
583 */
584function pqdownheap(s, tree, k)
585// deflate_state *s;
586// ct_data *tree; /* the tree to restore */
587// int k; /* node to move down */
588{
589 var v = s.heap[k];
590 var j = k << 1; /* left son of k */
591 while (j <= s.heap_len) {
592 /* Set j to the smallest of the two sons: */
593 if (j < s.heap_len &&
594 smaller(tree, s.heap[j + 1], s.heap[j], s.depth)) {
595 j++;
596 }
597 /* Exit if v is smaller than both sons */
598 if (smaller(tree, v, s.heap[j], s.depth)) { break; }
599
600 /* Exchange v with the smallest son */
601 s.heap[k] = s.heap[j];
602 k = j;
603
604 /* And continue down the tree, setting j to the left son of k */
605 j <<= 1;
606 }
607 s.heap[k] = v;
608}
609
610
611// inlined manually
612// var SMALLEST = 1;
613
614/* ===========================================================================
615 * Send the block data compressed using the given Huffman trees
616 */
617function compress_block(s, ltree, dtree)
618// deflate_state *s;
619// const ct_data *ltree; /* literal tree */
620// const ct_data *dtree; /* distance tree */
621{
622 var dist; /* distance of matched string */
623 var lc; /* match length or unmatched char (if dist == 0) */
624 var lx = 0; /* running index in l_buf */
625 var code; /* the code to send */
626 var extra; /* number of extra bits to send */
627
628 if (s.last_lit !== 0) {
629 do {
630 dist = (s.pending_buf[s.d_buf + lx * 2] << 8) | (s.pending_buf[s.d_buf + lx * 2 + 1]);
631 lc = s.pending_buf[s.l_buf + lx];
632 lx++;
633
634 if (dist === 0) {
635 send_code(s, lc, ltree); /* send a literal byte */
636 //Tracecv(isgraph(lc), (stderr," '%c' ", lc));
637 } else {
638 /* Here, lc is the match length - MIN_MATCH */
639 code = _length_code[lc];
640 send_code(s, code + LITERALS + 1, ltree); /* send the length code */
641 extra = extra_lbits[code];
642 if (extra !== 0) {
643 lc -= base_length[code];
644 send_bits(s, lc, extra); /* send the extra length bits */
645 }
646 dist--; /* dist is now the match distance - 1 */
647 code = d_code(dist);
648 //Assert (code < D_CODES, "bad d_code");
649
650 send_code(s, code, dtree); /* send the distance code */
651 extra = extra_dbits[code];
652 if (extra !== 0) {
653 dist -= base_dist[code];
654 send_bits(s, dist, extra); /* send the extra distance bits */
655 }
656 } /* literal or match pair ? */
657
658 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
659 //Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
660 // "pendingBuf overflow");
661
662 } while (lx < s.last_lit);
663 }
664
665 send_code(s, END_BLOCK, ltree);
666}
667
668
669/* ===========================================================================
670 * Construct one Huffman tree and assigns the code bit strings and lengths.
671 * Update the total bit length for the current block.
672 * IN assertion: the field freq is set for all tree elements.
673 * OUT assertions: the fields len and code are set to the optimal bit length
674 * and corresponding code. The length opt_len is updated; static_len is
675 * also updated if stree is not null. The field max_code is set.
676 */
677function build_tree(s, desc)
678// deflate_state *s;
679// tree_desc *desc; /* the tree descriptor */
680{
681 var tree = desc.dyn_tree;
682 var stree = desc.stat_desc.static_tree;
683 var has_stree = desc.stat_desc.has_stree;
684 var elems = desc.stat_desc.elems;
685 var n, m; /* iterate over heap elements */
686 var max_code = -1; /* largest code with non zero frequency */
687 var node; /* new node being created */
688
689 /* Construct the initial heap, with least frequent element in
690 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
691 * heap[0] is not used.
692 */
693 s.heap_len = 0;
694 s.heap_max = HEAP_SIZE;
695
696 for (n = 0; n < elems; n++) {
697 if (tree[n * 2]/*.Freq*/ !== 0) {
698 s.heap[++s.heap_len] = max_code = n;
699 s.depth[n] = 0;
700
701 } else {
702 tree[n * 2 + 1]/*.Len*/ = 0;
703 }
704 }
705
706 /* The pkzip format requires that at least one distance code exists,
707 * and that at least one bit should be sent even if there is only one
708 * possible code. So to avoid special checks later on we force at least
709 * two codes of non zero frequency.
710 */
711 while (s.heap_len < 2) {
712 node = s.heap[++s.heap_len] = (max_code < 2 ? ++max_code : 0);
713 tree[node * 2]/*.Freq*/ = 1;
714 s.depth[node] = 0;
715 s.opt_len--;
716
717 if (has_stree) {
718 s.static_len -= stree[node * 2 + 1]/*.Len*/;
719 }
720 /* node is 0 or 1 so it does not have extra bits */
721 }
722 desc.max_code = max_code;
723
724 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
725 * establish sub-heaps of increasing lengths:
726 */
727 for (n = (s.heap_len >> 1/*int /2*/); n >= 1; n--) { pqdownheap(s, tree, n); }
728
729 /* Construct the Huffman tree by repeatedly combining the least two
730 * frequent nodes.
731 */
732 node = elems; /* next internal node of the tree */
733 do {
734 //pqremove(s, tree, n); /* n = node of least frequency */
735 /*** pqremove ***/
736 n = s.heap[1/*SMALLEST*/];
737 s.heap[1/*SMALLEST*/] = s.heap[s.heap_len--];
738 pqdownheap(s, tree, 1/*SMALLEST*/);
739 /***/
740
741 m = s.heap[1/*SMALLEST*/]; /* m = node of next least frequency */
742
743 s.heap[--s.heap_max] = n; /* keep the nodes sorted by frequency */
744 s.heap[--s.heap_max] = m;
745
746 /* Create a new node father of n and m */
747 tree[node * 2]/*.Freq*/ = tree[n * 2]/*.Freq*/ + tree[m * 2]/*.Freq*/;
748 s.depth[node] = (s.depth[n] >= s.depth[m] ? s.depth[n] : s.depth[m]) + 1;
749 tree[n * 2 + 1]/*.Dad*/ = tree[m * 2 + 1]/*.Dad*/ = node;
750
751 /* and insert the new node in the heap */
752 s.heap[1/*SMALLEST*/] = node++;
753 pqdownheap(s, tree, 1/*SMALLEST*/);
754
755 } while (s.heap_len >= 2);
756
757 s.heap[--s.heap_max] = s.heap[1/*SMALLEST*/];
758
759 /* At this point, the fields freq and dad are set. We can now
760 * generate the bit lengths.
761 */
762 gen_bitlen(s, desc);
763
764 /* The field len is now set, we can generate the bit codes */
765 gen_codes(tree, max_code, s.bl_count);
766}
767
768
769/* ===========================================================================
770 * Scan a literal or distance tree to determine the frequencies of the codes
771 * in the bit length tree.
772 */
773function scan_tree(s, tree, max_code)
774// deflate_state *s;
775// ct_data *tree; /* the tree to be scanned */
776// int max_code; /* and its largest code of non zero frequency */
777{
778 var n; /* iterates over all tree elements */
779 var prevlen = -1; /* last emitted length */
780 var curlen; /* length of current code */
781
782 var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */
783
784 var count = 0; /* repeat count of the current code */
785 var max_count = 7; /* max repeat count */
786 var min_count = 4; /* min repeat count */
787
788 if (nextlen === 0) {
789 max_count = 138;
790 min_count = 3;
791 }
792 tree[(max_code + 1) * 2 + 1]/*.Len*/ = 0xffff; /* guard */
793
794 for (n = 0; n <= max_code; n++) {
795 curlen = nextlen;
796 nextlen = tree[(n + 1) * 2 + 1]/*.Len*/;
797
798 if (++count < max_count && curlen === nextlen) {
799 continue;
800
801 } else if (count < min_count) {
802 s.bl_tree[curlen * 2]/*.Freq*/ += count;
803
804 } else if (curlen !== 0) {
805
806 if (curlen !== prevlen) { s.bl_tree[curlen * 2]/*.Freq*/++; }
807 s.bl_tree[REP_3_6 * 2]/*.Freq*/++;
808
809 } else if (count <= 10) {
810 s.bl_tree[REPZ_3_10 * 2]/*.Freq*/++;
811
812 } else {
813 s.bl_tree[REPZ_11_138 * 2]/*.Freq*/++;
814 }
815
816 count = 0;
817 prevlen = curlen;
818
819 if (nextlen === 0) {
820 max_count = 138;
821 min_count = 3;
822
823 } else if (curlen === nextlen) {
824 max_count = 6;
825 min_count = 3;
826
827 } else {
828 max_count = 7;
829 min_count = 4;
830 }
831 }
832}
833
834
835/* ===========================================================================
836 * Send a literal or distance tree in compressed form, using the codes in
837 * bl_tree.
838 */
839function send_tree(s, tree, max_code)
840// deflate_state *s;
841// ct_data *tree; /* the tree to be scanned */
842// int max_code; /* and its largest code of non zero frequency */
843{
844 var n; /* iterates over all tree elements */
845 var prevlen = -1; /* last emitted length */
846 var curlen; /* length of current code */
847
848 var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */
849
850 var count = 0; /* repeat count of the current code */
851 var max_count = 7; /* max repeat count */
852 var min_count = 4; /* min repeat count */
853
854 /* tree[max_code+1].Len = -1; */ /* guard already set */
855 if (nextlen === 0) {
856 max_count = 138;
857 min_count = 3;
858 }
859
860 for (n = 0; n <= max_code; n++) {
861 curlen = nextlen;
862 nextlen = tree[(n + 1) * 2 + 1]/*.Len*/;
863
864 if (++count < max_count && curlen === nextlen) {
865 continue;
866
867 } else if (count < min_count) {
868 do { send_code(s, curlen, s.bl_tree); } while (--count !== 0);
869
870 } else if (curlen !== 0) {
871 if (curlen !== prevlen) {
872 send_code(s, curlen, s.bl_tree);
873 count--;
874 }
875 //Assert(count >= 3 && count <= 6, " 3_6?");
876 send_code(s, REP_3_6, s.bl_tree);
877 send_bits(s, count - 3, 2);
878
879 } else if (count <= 10) {
880 send_code(s, REPZ_3_10, s.bl_tree);
881 send_bits(s, count - 3, 3);
882
883 } else {
884 send_code(s, REPZ_11_138, s.bl_tree);
885 send_bits(s, count - 11, 7);
886 }
887
888 count = 0;
889 prevlen = curlen;
890 if (nextlen === 0) {
891 max_count = 138;
892 min_count = 3;
893
894 } else if (curlen === nextlen) {
895 max_count = 6;
896 min_count = 3;
897
898 } else {
899 max_count = 7;
900 min_count = 4;
901 }
902 }
903}
904
905
906/* ===========================================================================
907 * Construct the Huffman tree for the bit lengths and return the index in
908 * bl_order of the last bit length code to send.
909 */
910function build_bl_tree(s) {
911 var max_blindex; /* index of last bit length code of non zero freq */
912
913 /* Determine the bit length frequencies for literal and distance trees */
914 scan_tree(s, s.dyn_ltree, s.l_desc.max_code);
915 scan_tree(s, s.dyn_dtree, s.d_desc.max_code);
916
917 /* Build the bit length tree: */
918 build_tree(s, s.bl_desc);
919 /* opt_len now includes the length of the tree representations, except
920 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
921 */
922
923 /* Determine the number of bit length codes to send. The pkzip format
924 * requires that at least 4 bit length codes be sent. (appnote.txt says
925 * 3 but the actual value used is 4.)
926 */
927 for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
928 if (s.bl_tree[bl_order[max_blindex] * 2 + 1]/*.Len*/ !== 0) {
929 break;
930 }
931 }
932 /* Update opt_len to include the bit length tree and counts */
933 s.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
934 //Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
935 // s->opt_len, s->static_len));
936
937 return max_blindex;
938}
939
940
941/* ===========================================================================
942 * Send the header for a block using dynamic Huffman trees: the counts, the
943 * lengths of the bit length codes, the literal tree and the distance tree.
944 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
945 */
946function send_all_trees(s, lcodes, dcodes, blcodes)
947// deflate_state *s;
948// int lcodes, dcodes, blcodes; /* number of codes for each tree */
949{
950 var rank; /* index in bl_order */
951
952 //Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
953 //Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
954 // "too many codes");
955 //Tracev((stderr, "\nbl counts: "));
956 send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */
957 send_bits(s, dcodes - 1, 5);
958 send_bits(s, blcodes - 4, 4); /* not -3 as stated in appnote.txt */
959 for (rank = 0; rank < blcodes; rank++) {
960 //Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
961 send_bits(s, s.bl_tree[bl_order[rank] * 2 + 1]/*.Len*/, 3);
962 }
963 //Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
964
965 send_tree(s, s.dyn_ltree, lcodes - 1); /* literal tree */
966 //Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
967
968 send_tree(s, s.dyn_dtree, dcodes - 1); /* distance tree */
969 //Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
970}
971
972
973/* ===========================================================================
974 * Check if the data type is TEXT or BINARY, using the following algorithm:
975 * - TEXT if the two conditions below are satisfied:
976 * a) There are no non-portable control characters belonging to the
977 * "black list" (0..6, 14..25, 28..31).
978 * b) There is at least one printable character belonging to the
979 * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
980 * - BINARY otherwise.
981 * - The following partially-portable control characters form a
982 * "gray list" that is ignored in this detection algorithm:
983 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
984 * IN assertion: the fields Freq of dyn_ltree are set.
985 */
986function detect_data_type(s) {
987 /* black_mask is the bit mask of black-listed bytes
988 * set bits 0..6, 14..25, and 28..31
989 * 0xf3ffc07f = binary 11110011111111111100000001111111
990 */
991 var black_mask = 0xf3ffc07f;
992 var n;
993
994 /* Check for non-textual ("black-listed") bytes. */
995 for (n = 0; n <= 31; n++, black_mask >>>= 1) {
996 if ((black_mask & 1) && (s.dyn_ltree[n * 2]/*.Freq*/ !== 0)) {
997 return Z_BINARY;
998 }
999 }
1000
1001 /* Check for textual ("white-listed") bytes. */
1002 if (s.dyn_ltree[9 * 2]/*.Freq*/ !== 0 || s.dyn_ltree[10 * 2]/*.Freq*/ !== 0 ||
1003 s.dyn_ltree[13 * 2]/*.Freq*/ !== 0) {
1004 return Z_TEXT;
1005 }
1006 for (n = 32; n < LITERALS; n++) {
1007 if (s.dyn_ltree[n * 2]/*.Freq*/ !== 0) {
1008 return Z_TEXT;
1009 }
1010 }
1011
1012 /* There are no "black-listed" or "white-listed" bytes:
1013 * this stream either is empty or has tolerated ("gray-listed") bytes only.
1014 */
1015 return Z_BINARY;
1016}
1017
1018
1019var static_init_done = false;
1020
1021/* ===========================================================================
1022 * Initialize the tree data structures for a new zlib stream.
1023 */
1024function _tr_init(s)
1025{
1026
1027 if (!static_init_done) {
1028 tr_static_init();
1029 static_init_done = true;
1030 }
1031
1032 s.l_desc = new TreeDesc(s.dyn_ltree, static_l_desc);
1033 s.d_desc = new TreeDesc(s.dyn_dtree, static_d_desc);
1034 s.bl_desc = new TreeDesc(s.bl_tree, static_bl_desc);
1035
1036 s.bi_buf = 0;
1037 s.bi_valid = 0;
1038
1039 /* Initialize the first block of the first file: */
1040 init_block(s);
1041}
1042
1043
1044/* ===========================================================================
1045 * Send a stored block
1046 */
1047function _tr_stored_block(s, buf, stored_len, last)
1048//DeflateState *s;
1049//charf *buf; /* input block */
1050//ulg stored_len; /* length of input block */
1051//int last; /* one if this is the last block for a file */
1052{
1053 send_bits(s, (STORED_BLOCK << 1) + (last ? 1 : 0), 3); /* send block type */
1054 copy_block(s, buf, stored_len, true); /* with header */
1055}
1056
1057
1058/* ===========================================================================
1059 * Send one empty static block to give enough lookahead for inflate.
1060 * This takes 10 bits, of which 7 may remain in the bit buffer.
1061 */
1062function _tr_align(s) {
1063 send_bits(s, STATIC_TREES << 1, 3);
1064 send_code(s, END_BLOCK, static_ltree);
1065 bi_flush(s);
1066}
1067
1068
1069/* ===========================================================================
1070 * Determine the best encoding for the current block: dynamic trees, static
1071 * trees or store, and output the encoded block to the zip file.
1072 */
1073function _tr_flush_block(s, buf, stored_len, last)
1074//DeflateState *s;
1075//charf *buf; /* input block, or NULL if too old */
1076//ulg stored_len; /* length of input block */
1077//int last; /* one if this is the last block for a file */
1078{
1079 var opt_lenb, static_lenb; /* opt_len and static_len in bytes */
1080 var max_blindex = 0; /* index of last bit length code of non zero freq */
1081
1082 /* Build the Huffman trees unless a stored block is forced */
1083 if (s.level > 0) {
1084
1085 /* Check if the file is binary or text */
1086 if (s.strm.data_type === Z_UNKNOWN) {
1087 s.strm.data_type = detect_data_type(s);
1088 }
1089
1090 /* Construct the literal and distance trees */
1091 build_tree(s, s.l_desc);
1092 // Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
1093 // s->static_len));
1094
1095 build_tree(s, s.d_desc);
1096 // Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
1097 // s->static_len));
1098 /* At this point, opt_len and static_len are the total bit lengths of
1099 * the compressed block data, excluding the tree representations.
1100 */
1101
1102 /* Build the bit length tree for the above two trees, and get the index
1103 * in bl_order of the last bit length code to send.
1104 */
1105 max_blindex = build_bl_tree(s);
1106
1107 /* Determine the best encoding. Compute the block lengths in bytes. */
1108 opt_lenb = (s.opt_len + 3 + 7) >>> 3;
1109 static_lenb = (s.static_len + 3 + 7) >>> 3;
1110
1111 // Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
1112 // opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
1113 // s->last_lit));
1114
1115 if (static_lenb <= opt_lenb) { opt_lenb = static_lenb; }
1116
1117 } else {
1118 // Assert(buf != (char*)0, "lost buf");
1119 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
1120 }
1121
1122 if ((stored_len + 4 <= opt_lenb) && (buf !== -1)) {
1123 /* 4: two words for the lengths */
1124
1125 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
1126 * Otherwise we can't have processed more than WSIZE input bytes since
1127 * the last block flush, because compression would have been
1128 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
1129 * transform a block into a stored block.
1130 */
1131 _tr_stored_block(s, buf, stored_len, last);
1132
1133 } else if (s.strategy === Z_FIXED || static_lenb === opt_lenb) {
1134
1135 send_bits(s, (STATIC_TREES << 1) + (last ? 1 : 0), 3);
1136 compress_block(s, static_ltree, static_dtree);
1137
1138 } else {
1139 send_bits(s, (DYN_TREES << 1) + (last ? 1 : 0), 3);
1140 send_all_trees(s, s.l_desc.max_code + 1, s.d_desc.max_code + 1, max_blindex + 1);
1141 compress_block(s, s.dyn_ltree, s.dyn_dtree);
1142 }
1143 // Assert (s->compressed_len == s->bits_sent, "bad compressed size");
1144 /* The above check is made mod 2^32, for files larger than 512 MB
1145 * and uLong implemented on 32 bits.
1146 */
1147 init_block(s);
1148
1149 if (last) {
1150 bi_windup(s);
1151 }
1152 // Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1153 // s->compressed_len-7*last));
1154}
1155
1156/* ===========================================================================
1157 * Save the match info and tally the frequency counts. Return true if
1158 * the current block must be flushed.
1159 */
1160function _tr_tally(s, dist, lc)
1161// deflate_state *s;
1162// unsigned dist; /* distance of matched string */
1163// unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
1164{
1165 //var out_length, in_length, dcode;
1166
1167 s.pending_buf[s.d_buf + s.last_lit * 2] = (dist >>> 8) & 0xff;
1168 s.pending_buf[s.d_buf + s.last_lit * 2 + 1] = dist & 0xff;
1169
1170 s.pending_buf[s.l_buf + s.last_lit] = lc & 0xff;
1171 s.last_lit++;
1172
1173 if (dist === 0) {
1174 /* lc is the unmatched char */
1175 s.dyn_ltree[lc * 2]/*.Freq*/++;
1176 } else {
1177 s.matches++;
1178 /* Here, lc is the match length - MIN_MATCH */
1179 dist--; /* dist = match distance - 1 */
1180 //Assert((ush)dist < (ush)MAX_DIST(s) &&
1181 // (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1182 // (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1183
1184 s.dyn_ltree[(_length_code[lc] + LITERALS + 1) * 2]/*.Freq*/++;
1185 s.dyn_dtree[d_code(dist) * 2]/*.Freq*/++;
1186 }
1187
1188// (!) This block is disabled in zlib defaults,
1189// don't enable it for binary compatibility
1190
1191//#ifdef TRUNCATE_BLOCK
1192// /* Try to guess if it is profitable to stop the current block here */
1193// if ((s.last_lit & 0x1fff) === 0 && s.level > 2) {
1194// /* Compute an upper bound for the compressed length */
1195// out_length = s.last_lit*8;
1196// in_length = s.strstart - s.block_start;
1197//
1198// for (dcode = 0; dcode < D_CODES; dcode++) {
1199// out_length += s.dyn_dtree[dcode*2]/*.Freq*/ * (5 + extra_dbits[dcode]);
1200// }
1201// out_length >>>= 3;
1202// //Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1203// // s->last_lit, in_length, out_length,
1204// // 100L - out_length*100L/in_length));
1205// if (s.matches < (s.last_lit>>1)/*int /2*/ && out_length < (in_length>>1)/*int /2*/) {
1206// return true;
1207// }
1208// }
1209//#endif
1210
1211 return (s.last_lit === s.lit_bufsize - 1);
1212 /* We avoid equality with lit_bufsize because of wraparound at 64K
1213 * on 16 bit machines and because stored blocks are restricted to
1214 * 64K-1 bytes.
1215 */
1216}
1217
1218exports._tr_init = _tr_init;
1219exports._tr_stored_block = _tr_stored_block;
1220exports._tr_flush_block = _tr_flush_block;
1221exports._tr_tally = _tr_tally;
1222exports._tr_align = _tr_align;
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